ASNS is encoded on chromosome 7 and has 14 exons. The promoter begins 173 bases upstream of the start codon, which is on exon 4, with three GC-rich sequences (GC-I, GC-II, and GC-III) followed by two nutrient sensing response elements, NSRE-1 (ATGATGAAA; at nt -70) and NSRE-2 (GTTACA; at nt -49). The stop codon is on exon 14.

The full length transcript (RefSeq variant 1; NM_133436 on Fig1) is 2348 bp long. Ten alternative splicing isoforms have been reported with most variation occurring primarily in the 5UTR.
Various forms of cellular stress, including nutrient deprivation, lead to increased ASNS transcription. One component of that mechanism includes translation of the activating transcription factor family of proteins (ATF2, ATF3, ATF4, ATF5, and ATF6), all of which increase ASNS transcription through binding to NSRE-1 and/or NSRE-2. TRB3 is a negative feedback regulator of ATF4-dependent transcription, and C/EBP-beta is a negative regulator of ATF5-dependent transcription. DDIT3/CHOP is also a negative regulator of ASNS transcription.
ASNS has also been reported to be a significant target of transactivation by mutant p53, whereas wild-type p53 inhibits transcriptional activation of the NSREs.
ASNS mRNA has been shown to exhibit a half-life of 9 h and periodic, clock-like up-regulation every around 35 min in cell culture.

Transcripts NM_001673, NM_133436, NM_183356, BC008723, BC014621, BT007113, and M27396 encode a common 561 aa (64 kDa) ASNS protein sequence. Transcripts AK302189 and M15798 encode 540 aa N-terminally truncated proteins that differ in sequence between amino acids 312-322 and 332-339. Transcript AK302242 encodes a 478 aa isoform that is further truncated at the N-terminus.

Only the 561 aa isoform has been experimentally confirmed, and it has been found to be up-regulated by nutrient deprivation. Its half-life is reported to be 43-46 h.

ASNS protein is cytoplasmic, but prediction algorithms also predict a small fraction of nuclear localization.

ASNS catalyzes the synthesis of asparagine from glutamine and aspartic acid. In addition to providing asparagine for global protein synthesis, ASNS expression appears to be required for the transition from G1 to S phase of the cell cycle.

The 561 aa ASNS isoform has 29% identity with a protein called asparagine synthetase domain containing 1 (ASNSD1) that is 643 aa in length and encoded by a transcript (NM_019048) produced by chromosome 2.

A total of 136 SNPs have been reported in the ASNS gene region thus far, and 9 of these are coding SNPs: C1820A (P547H); C1399T (R407X); C1389G (L403L); 1299G (G373-frameshift); G1009A (A277T); T809A (V210E); A546T (A122A); G524C (C115S); C324T (H48H). Of those nine coding SNPs, only V210E has been validated by multiple independent groups including the HapMap Project. None of the SNPs has thus far been clinically associated with a disease or drug response phenotype.

All reported SNPs appear to be of germline origin.

None of the reported SNPs have been associated with tumor initiation or progression.